How do you do this statistic question?

Richard know s three women: Pat, Jan, Nancy. He asks Pat for a date 1/2 the time, and jan 1/3 of the time and nancy 1/6 the time. The probability that pat will accept his invitation is .3, that jan will accept is .7, and that nancy willa ccept is .5. Given that richard and one of the three women were out on a date last night what is the probability that richard was out with jen?